My SawStop may have just injured itself!

[Stephen Roth]

I was using the SawStop (Industrial Model) with a Systematic Dado blade. (8" with all cutters installed.) The aluminum miter gauge hit the blade and WHAM!, the trigger activated. I have had the trigger activate before when I forgot that there was metal involved (such as cutting aluminum foil coated foam insulation), but this activation seemed much kinetic. In fact, the brake got shredded and sheared off teeth from the dado blade. Not just the carbide -- the actual teeth. (See pics.)

I figured I would check the alignment of the blade to the miter gauge, and found that it was out of alignment by .011" I usually can align the saw to .001, so I realigned it with an alignment plate and got it back to .001. But when I put on a blade, I found out the alignment was still out .007, depending on how I rotated the blade. For example, +.005 and then rotated 180 degrees and out by -.002. And the reverse in another 180. So I figured I would check the runout of the arbor flange, which the factory specs list as having a .001 tolerance. Mine was now .002. That does not seem like a lot, but taking the radius of the flange out to the edge of the blade would increase it at least 3-4 times, which translates to a .007 wobble in the blade plate.

Also, the cut quality is certainly inferior to what it had been before. Previously, I could get a glass smooth cut-off with a Forrest Cross-cut blade, and now I can see tooth marks. Also, the saw makes a slightly different sound. Like there is more vibration.

I called SawStop, and they say the tolerance for blade wobble is .010 and that I should not have used a dado with full cutters. (Note that they only recently recommend this practice, probably because the saw cannot stop a spinning billet of 8" x 3/4" metal.)

I can't believe .010 wobble is acceptable, especially when the SawStop manual describes that you can get to .001. And .010 is bad. Darn, I can measure .010 without a dial indicator. SawStop said the flange run-out was over spec, but not bad. This is where I got into a debate with the rep as to whether .002 was only a thou. more than .001, or was double .001!!!

So here are my questions:

1. Do others regularly get blade/mite slot alignment close to .001. I can't believe that 10 times that (i.e. .010) is within tolerance for this type of saw.

2. SawStop said I could replace the arbor assembly for $250. Has anyone else replaced that part? Seems like it would be a bear. (FYI, it upsets me that SawStop would not send that to me a this seems like a problem that they did not know to tell people about until it arose.)

Thanks in advance. 424655424656424657

[Joe Rogers]

This is what I call being on the expensive end of the learning curve. You state you have had several brake events. The problem with the saw stop activation is it is a “cost of doing business”. It is a shame that current recommendations against a stacked dado arrived post activation. That said, any activation has a cost attached and this one is real expensive. I wish that Saw Stop would help out here by offering the arbor at a significant discount due to circumstances but if not I guess I would still replace it on my dime and in the future be EXTREMELY careful with any metal near the saw blade.
Joe

[Kevin Jenness]

Sounds like you need to replace the arbor- too bad. Maybe if you complain farther up the chain SS will reduce the price. Still, between a new arbor, brake and dado set an expensive error. If it were skin contact the repair would seem quite cheap. As is, well, you'll probably remember to keep metal out of the blade in future.

[David Utterback]

"that I should not have used a dado with full cutters."

Could you please explain what kind of cutters these are? Thanks

[mike stenson]

A full dado stack? That's a lot of mass rotating, and a lot grabbing at the stop. I'm not surprised that something else had to give.

[Stephen Roth]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

[Stephen Roth]

Yes, it is an expensive error. But I'm happy that the saw has this feature. In fact, I bought the saw when I started working with my 12 year old son and his friends in the shop. I told my wife that if the whole saw had to be replaced when it saved cutting off some kid's finger, it would be worth it.

[Frank Pratt]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

They've been including that in their manual for at least as long as I've had mine, about 5 years.

[Frank Pratt]

I tripped mine once when cutting a board with some graphite cloth glued to it :( It also took a couple of teeth from the blade disk.

[Brian Holcombe]

Most likely bent the arbor. I can’t imagine these operate without bending the arbor.

.010” wobble is terrible, should be negligible IMO.

[Jim Dwight]

I am a bit confused about the difference between your dado set, the one that was damaged, and what SawStop recommends. I looked up Systematic dado sets and the picture shows simple wing, two tooth, chippers (outside blades differ in tooth count for two different models). But you seem to describe interior blades I am calling chippers as full blades. Did Systematic made a different set previously?

I do not doubt that the effect of the cartridge activating on a dado blade was more violent but any cartridge activation is violent. I also think the effect may have been cumulative.

I don't know anything about the arbor but before I spent $250 for a new one I would look into bearing replacement. The arbor could be bent but I doubt it. Seems more likely to me that the bearing might be damaged. The repeatability you describe, however, works against this theory. If you can get the arbor out and roll it on a flat surface it would tell you.

[Stephen Roth]

I agree. I can't believe SawStop says a .010 blade misalignment is within tolerance. In fact, when I said that, I responded "INCHES! You must mean milimeters!"

[Corey Pelton]

When I bought my PCS a couple years back, I was having trouble getting the blade aligned to the miter slot. I figured the blade was out of whack. I threw on every blade I had, and it still gave the same error on the opposite side of the blade. After chatting with SawStop support, they surmised the arbor had an issue. They shipped me out a new arbor block. After installing the new arbor block, the issue was gone. Bit of a pain in the ass, but all's well that ends well.

[Ben Rivel]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."
Is the Forrest Dado King not considered an expensive one? Because it comes with the "chipper" inner blades, not full sized ones.

[Wade Lippman]

..

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

I bought my SS about 7 years ago and I am reasonably sure that was their recommendation back then.

[Dave Sabo]

To some, this will seem like stirring the pot.

This has always been the biggest drawback to me of the SS system- it destroys blades.

Kudos to Gass and co. for getting the idea to market, but I suspect that better mousetraps like Bosch's reaxx and Alt
endorf's ASA will eventually replace sawstop because they don't ruin tooling.

[Johnny Barr]

The warning of using the wrong dado types from SS has been around a long time, at least 5 years pushing 10. I ended up selling my wonderful Freud set (SD 508) to get one of their recommended types. That list of suitable sets has also been around a long time. I even wrote to them about the Freud set and they said it wasn't suitable. I also got the 0.010" tolerance rubbish from them between blade and slot. How could you accept that? I adjusted it to 0.001" which is easy on my PCS

[Thomas McCurnin]

Interesting information. I did not know that.

I don't have a saw stop and having this feature would probably not make it a deal breaker. But it does sound like a trade off.

If the saw detects an object (your finger) in the saw blade it throws a quick brake to the arbor, saving the object from serious destruction but destroying the arbor in the process.

[David Utterback]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

Thank you for this information.

[mreza Salav]

I have replaced arbor assembly before.
Recommendation of not using daado bladws with full middle cutters have been in the manual since 11 years ago. Definitely not a new thing.

[Brian Tymchak]

If the saw detects an object (your finger) in the saw blade it throws a quick brake to the arbor, saving the object from serious destruction but destroying the arbor in the process.

More correctly the blade brake hits the saw blade, not the arbor, as the pictures in the original post clearly demonstrated. I think you are drawing too broad off a conclusion. It is my humble opinion that the arbor damage, if that is what truly happened, in the original post is likely aggravated by the large rotating mass of the full dado stack. I've seen the Sawstop brake engage on a standard blade and destroy the blade, but not the arbor.

[Stephen Roth]

Thanks. My manual didn't have it. But I am glad that SawStop is warning people about it. I guess like all engineering fixes, others must have experienced the problem and SawStop made the correction.

By the way, why did you have to change the arbor?

------------ FYI for the readers, I have had three activations in 10 years. The first two (cutting aluminized foam, and hitting the miter guage with the dado blade) were clear SawStop user mistakes. My third activation was hitting a screw that was holding down a plastic handle to a jig. I was surprised that the detection feature was able to sense my hand through the plastic handle. But I guess I would rather have it activate than not. So I'm considering that one to be a "save."

[Stephen Roth]

I agree with Brian. Hitting a normal blade has not damaged the saw. The brake just jams into the blade teeth and stops the rotation within one or two teeth. Amazing in fact. (And it drops the blade/arbor assembly down at the same time.)

But the full dado stack is a huge hunk of metal. And I was using all the cutters. ( I'm sure some engineer can calculate the force of that deacceleration. It must be huge. I calculate the weight of the blade at 10.7 pounds!)

[George Yetka]

Is the Forrest Dado King not considered an expensive one? Because it comes with the "chipper" inner blades, not full sized ones.

It is an excellent one, it is what I run(and love). But Im sure there are more expensive ones available It seems most have chipper inners now.

[Frank Pratt]

More correctly the blade brake hits the saw blade, not the arbor, as the pictures in the original post clearly demonstrated. I think you are drawing too broad off a conclusion. It is my humble opinion that the arbor damage, if that is what truly happened, in the original post is likely aggravated by the large rotating mass of the full dado stack. I've seen the Sawstop brake engage on a standard blade and destroy the blade, but not the arbor.

This is correct. The local Lee Valley store has demo'd the SawStop brake probably dozens of times with no ill effect on the arbor.

[mike stenson]

It is an excellent one, it is what I run(and love). But Im sure there are more expensive ones available It seems most have chipper inners now.

Less rotating mass, they come up to speed faster, and stop faster. There's also really not a huge benefit from a full plate. For reference, if the 10.7lbs is correct, that's more rotating mass than the wheels on my car.

[Thomas McCurnin]

In any event, not using a full scale dado set would be a deal breaker for me. I use the dados for 3/4 plywood projects, and would have to use a router.

[John Lanciani]

For reference, if the 10.7lbs is correct, that's more rotating mass than the wheels on my car.


Not likely, F1 magnesium wheel with tire is +/- 10 kg (22 lbs.), Konigsegg carbon fiber rim only is 13 lbs. Then add the hub and brake disc...

[mike stenson]

Not likely, F1 magnesium wheel with tire is +/- 10 kg (22 lbs.), Konigsegg carbon fiber rim only is 13 lbs. Then add the hub and brake disc...

Wow, you're right. I have no idea what I was thinking there. ROTOR, not wheel.

[Frank Pratt]

In any event, not using a full scale dado set would be a deal breaker for me. I use the dados for 3/4 plywood projects, and would have to use a router.

The SawStop handles full size dado sets fine. I've done cuts with all the chippers & all the spacers and it ran perfectly. I didn't have a brake activation, but SawStop doesn't say don't do it.

[Stephen Roth]

Thomas, you can use a 3/4 dado set. You just have to use a set with the partial plate chippers. See the discussion above. I don't think you can use a 10" one though.

[michael dilday]

Most likely bent the arbor. I can’t imagine these operate without bending the arbor.

.010” wobble is terrible, should be negligible IMO.

Actually mine has activated 3 times since I have owned it and my arbor is not bent.

[Tom Bender]

There's a cure for this that might save a few blades as well. Slow the saw down. I put a VFD and a slower motor on my Delta and it works great. It spins the blade at half speed or less. Half speed means 1/4 the energy. Unless you need production rates the slower feed is inconsequential. The quieter saw is nicer to use.